THE ATMOSPHERIC STANDARD

ATMOSPHERIC PRESSURE - Pressure exerted by the weight of the atmosphere standard atmospheric pressure is 101.325 kPa or 1.01325 bars or 14.696 psia or 29.921 inches of mercury at sea level. 

The K-model of Eq. (10.81) is a substantial simplihcation, because it is based on the assumption that the eddy coefficient and the wind speeds are constants. In addition, many of the parameters of influence on atmospheric dispersion presented above cannot be accounted for. This motivated numerous further developments. If the following relationship between the eddy coefficient an the atmospheric standard deviation is used... 

Calculation of the atmospheric TBP is rapid if it can be assumed that this distillation is ideal (which is not always the case in reality). It is only necessary to arrange the components in order of increasing boiling points and to accumulate the volumes determined by using the standard specific gravity. 

One standard method for determining the dissolved O2 content of natural waters and wastewaters is the Winkler method. A sample of water is collected in a fashion that prevents its exposure to the atmosphere (which might change the level of dissolved O2). The sample is then treated with a solution of MnS04, and then with a solution of NaOH and KI. Under these alkaline conditions Mn + is oxidized to Mn02 by the dissolved oxygen. 

Fowlef measured the turbidity of air at Mt. Wilson, California, on a clear day in 1913. Values of rx for dry air at different wavelengths are tabulated below, where x is essentially the thickness of the atmosphere corrected to standard temperature and pressure (STP) conditions ... 

Ain pollution (qv), lecognized in the National Ambient Aii Quality Standards (NAAQS) as being chaiactetized by a time—dosage lelationship, is defined as the presence in the atmosphere (or ambient ain) of one or more contaminants of such quantity and duration as may be injutious to human, plants, or animal life, property, or conduct of business (1,2). Thus, ain pollutants may be rendered less harmhil by reducing the concentration of contaminants, the exposure time, or both. 

Emissions from methanol vehicles are expected to produce lower HC and CO emissions than equivalent gasoline engines. However, methanol combustion produces significant amounts of formaldehyde (qv), a partial oxidation product of methanol. Eormaldehyde is classified as an air toxic and its emissions should be minimized. Eormaldehyde is also very reactive in the atmosphere and contributes to the formation of ozone. Emissions of NO may also pose a problem, especiaHy if the engine mns lean, a regime in which the standard three-way catalyst is not effective for NO reduction. 

Pressure. Standard atmospheric pressure is defined to be the force exerted by a column of mercury 760-mm high at 0°C. This corresponds to 0.101325 MPa (14.695 psi). Reference or fixed points for pressure caUbration exist and are analogous to the temperature standards cited (23). These points are based on phase changes or resistance jumps in selected materials. For the highest pressures, the most rehable technique is the correlation of the wavelength shift, /SX with pressure of the mby, R, fluorescence line and is determined by simultaneous specific volume measurements on cubic metals... 

In the United States, the reportable quantity of 1-propanol for spills under CERCLA "Superfund" is 100 Ib/d (45.4 kg/d). However, no reportable quantity is assigned for transport (43). The substance is on the list for atmospheric standards, as defined iu 40 CER 60.489 (47). The iatent of these standards is to require all newly constmcted, modified, and reconstmcted manufacturiug units to use the best demonstrated system of continuous emission reduction for equipment leaks of volatile organic compounds (47). 1-Propanol is also on the right-to-know regulations of the states of Connecticut,... 

Magnetic filters have been used to clean paint sHps and Hquids. Filters that are open to the atmosphere or closed, ie, pressure type, are available where the filter inlets are matched to standard pipe connections from 10 to 50 mm, for low capacity appHcations. 

In the fire codes, the atmospheric boiling point is an important physical property used to classify the degree of hazardousness of a Hquid. If a mixture of Hquids is heated, it starts to bod at some temperature but continues to rise ia temperature over a boiling temperature range. Because the mixture does not have a definite boiling poiat, the NFPA fire codes define a comparable value of boiling poiat for the purposes of classifying Hquids. For petroleum mixture, it is based on the 10% poiat of a distillation performed ia accordance with ASTM D86, Standard Method of Test for Distillation of Petroleum Products. 

Sihcon carbide has been described as a mild inhalation irritant (143). The threshold limit value for siUcon carbide in the atmosphere is 5 mg/m. Because of increased interest in SiC whiskers as a reinforcement for composites, the ASTM has estabUshed Subcommittee E34.70 on Single-Crystal Ceramic Whiskers to write standards for handling this form of SiC (144). 

A solution of sulfur trioxide [7446-11-9] dissolved in chlorosulfonic acid [7990-94-5] CISO H, has been used as a smoke (U.S. designation FS) but it is not a U.S. standard agent (see Chlorosulfuric acid Sulfuric acid and sulfur trioxide). When FS is atomized in air, the sulfur trioxide evaporates from the small droplets and reacts with atmospheric moisture to form sulfuric acid vapor. This vapor condenses into minute droplets that form a dense white cloud. FS produces its effect almost instantaneously upon mechanical atomization into the atmosphere, except at very low temperatures. At such temperatures, the small amount of moisture normally present in the atmosphere, requires that FS be thermally generated with the addition of steam to be effective. FS can be used as a fill for artillery and mortar shells and bombs and can be effectively dispersed from low performance aircraft spray tanks. FS is both corrosive and toxic in the presence of moisture, which imposes limitations on its storage, handling, and use. 

Colorfastness to burnt gas fumes, ISO 105-G02 is similar to GOl except that the specimen and standards are exposed to the fumes from a burning butane gas flame. Colorfastness to o2one ia the atmosphere, ISO 10S-G03, is done as GOl but uses o2one. 

Evaporative Emission. Fumes emitted from stored fuel or fuel left in the fuel dehvery system are also regulated by U.S. EPA standards. Gasoline consists of a variety of hydrocarbons ranging from high volatility butane (C-4) to lower volatility C-8 to C-10 hydrocarbons. The high volatility HCs are necessary for cold start, and are especially necessary for temperatures below which choking is needed to start the engine. Stored fuel and fuel left in the fuel system evaporates into the atmosphere. 

TABLE 2-236 Thermodynamic Properties of the International Standard Atmosphere ... 

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